1. Field of the Invention
The present invention relates to a handy tube pump for use in pumping a liquid from one place, such as a tank, to another, such as a vessel, under pressure provided by a hand-operated bellows member.
2. Description of the Prior Art
Handy pumps made of a plastic tube are known, and widely used for supplying fuel to oil heaters. The tube pump has a suction tube and a discharge tube. The suction tube is inserted in an oil tank at one end, and the discharge tube is inserted in the heater at its terminating end. In addition, the pump is provided with a bellows member communicating with the suction tube and the discharge tube, the bellows member having a small opening at its top. When the oil in the tank is to be sucked, the opening is closed, and the bellows member is gripped in the user's palm several times so that oil is transferred from the oil tank to a heat tank. When the heater tank is filled, the opening is opened. Usually the opening is closed by a cap. The known tube pumps have an internally threaded cap, which is screwed to the bellows member. When the cap is loosened thereby to open the opening, the user must turn the cap by hand. This requires the user to use his both hands, that is, with one hand the bellows member is operated, and with the other the cap is loosened. By loosening the cap, the pressure inside the bellows member is allowed to escape through the opening, thereby stopping the supplying of the fuel to the heater.